A person skilled in the art will recognize that in a lead locomotive, the throttle controller assembly receives signals from the central processor unit for control of locomotive engine, dynamic braking, and other locomotive functions. Based on the signals received from the central processor unit, the throttle controller assembly applies signals to the trainline, which is a multi strand electrical cable. The trainline conveys these signals to the functions being controlled. For example, the dynamic brake system is controlled by an analog voltage signal applied to one of the strands which is referred to in the art as the "24T trainline". For a consist of locomotives which are coupled together, the trainline cable is connected between locomotives. The controlled locomotives are controlled by signals on the trainline generated by the throttle controller of the lead locomotive, based on signals from the central processor unit of the lead locomotive.
It is quite well known in the railway industry, prior to the present invention, that the throttle controller assemblies used in a railway type locomotive are almost exclusively of the mechanical type. Mechanical type throttle controller assemblies of the prior art have normally utilized a number of mechanical devices in order to achieve actuation of the necessary microswitches and/or contacts. It is equally well known, for example, that cams are used extensively in this application in order to achieve the required actuation of the various microswitches and/or contacts disposed in the mechanical type throttle controller.
Such mechanical type throttle controllers which are presently being used on railway locomotives exhibit a number of relatively serious drawbacks and/or other limitations. These limitations have become more pronounced as the length of freight trains has grown in modern railroading, because the use of more and more locomotives are now required in a train consist in order to pull and/or push the added loads being hauled. For example, these mechanical type throttle controllers utilize either microswitches or contacts to control the voltage that is being applied to the trainline. Furthermore, there is no provision in these prior art mechanical throttle controllers for possible shut down of the system in the event of an output over current.
Additionally, these mechanical type throttle controllers are not equipped to provide the operator of the locomotive with any important feedback information and, consequently, they may not recognize a potential failure situation. Throttle controllers of the mechanical type also utilize either a resistive type voltage divider or a high power potentiometer in order to control the voltage and they are not equipped for shutdown of voltage regulation.
The prior art mechanical throttle controllers normally provide labels over each of the mechanical handles to convey only the position of the handle to the locomotive operator. However, these mechanical type throttle controllers are not equipped to display certain other relevant information, such as various diagnostic information, status information and/or warning type messages.
Furthermore, in a situation where it is either desirable or necessary to provide the required throttle control from a remote host over the communication lines, the currently used mechanical type throttle controllers require that a number of additional relays be used.
It can be seen from the above discussion of the prior art mechanical type throttle controller assemblies, presently used in the railroad industry, that there is an unfilled need which exists in the modern railroad industry for an improved railway locomotive type throttle controller assembly which will provide enhanced performance capability, additional functions which are not possible to accomplish with the prior art mechanical type throttle controllers and more consistent reliability. It is evident that this need has been addressed by each of the present invention and the closely related additional inventions which are being filed concurrently herewith.